1. Field of the Invention
The present invention relates to a peel-apart type image reproducing device in which rolled strip-like photosensitive material is cut into photosensitive sheets one by one, the photosensitive sheet is overlaid with a developer-containing pod and a transfer sheet, to burst the pod thereby transferring and visualizing latent images formed on the photosensitive sheet to a transfer sheet. Particularly, it relates to an image reproducing device having features in the detection for the rear end of a photosensitive film and applying different controls depending on the detected state.
2. Discussion of the Background
The image reproducing device using the peel-apart type instant photographic film of the aforementioned type is adapted such that a rolled photosensitive film is pulled out to an exposure position, a photosensitive sheet formed by cutting the photosensitive film into a predetermined length and a transfer sheet transported from a predetermined position under a controlled timing are overlaid over each other with a developer-containing pod put between them, and the sealing portion of the pod is bursted under a roller pressure to cast the developer uniformly between both of them, thereby developing a latent image formed on the photosensitive sheet and transferring the thus developed latent image to the transfer sheet.
Referring more specifically to the developing section, it is necessary that the developer is uniformly cast between the photosensitive sheet and the transfer sheet. Accordingly, the development is conducted by passing both of the photosensitive sheet and the transfer sheet between a pair of rollers having a minute gap called developing rollers. In view of the above, an excess amount of developer is required for the image formation in order to prevail the developer sufficiently as far as the rear end of the transfer sheet and the excess developer is stored at the rear end of the sheet. In this case, it is intended that the developer not exude beyond the edge of the sheet to contaminate the inside of the copying machine. In addition, the photosensitive sheet is formed to be longer by a length required for the transportation than the length of the photosensitive sheet required for the actually set number of sheets, for example, 36 sheets.
On the other hand, it has been known in an electro-facsimile machine using a rolled zinc oxide photosensitive paper that the rear end of the rolled photosensitive paper is detected by a marking applied to the rear end of the paper and the rolled photosensitive paper is discharged as it is out of the machine by a pair of pressure rollers with no cutting.
As for related arts relating to the present invention, U.S. Ser. No. 196,604 filed on May 20, 1988, U.S. Ser. No. 277,948 filed on Nov. 30, 1988 and Service manual No. 4 of BS470, pp. 56 to 58, published by Ricoh company Ltd. on June 1981 JAPAN.
However, if the rolled photosensitive paper discharging system in the electrofocsimile machine is applied as it is to the peel-apart type image reproducing device, since the marking position is situated at the final end and the remaining length can not previously be judged, if the photosensitive film cut by the cutting means is shorter than that for one sheet length set for the image formation, the developer cast between both of the sheets exudes from the rear end of the photosensitive sheet and the transfer sheet, to then adhere to the developing rollers. As a result, it contaminates the inside of the machine, including the developing rollers, impaires the circularity of the developing rollers, thereby bringing about undesirable effects such as uneven density in the formed image or causing troubles due to the adhesion of the developer from the developing rollers to the further equipment in the machine.
In addition, in a case where an image is not formed at a predetermined position but the image forming position is displaced rearwardly because of jamming, the photosensitive film of the final sheet may occasionally be cut in the middle. In this case, since the transfer sheet and the pod are consumed based on the cut photosensitive film, although no complete image can be formed, it results in the wasteful consumption of the photosensitive film, the transfer sheet and the developer, which is not economical. On the other hand, if the photosensitive film is formed longer than the previously set number of image forming sheets as described above, if all of the images are formed completely at predetermined positions, the additional length part is used wastefully to also invite economical disadvantage. Since silver salt is used for the photosensitive film, this results in an additional cost.
Furthermore, if the final sheet of the photosensitive film is cut at an intermediate portion and the distance between the cut portion and the final end of the photosensitive film is shorter than the distance between the conveyor rollers disposed on both sides of the cutting means, the portion of the photosensitive film from the cut portion to the final end can not be transported, causing jamming in the machine, which necessitates taking out the photosensitive film by opening the copying machine on every jamming, resulting in a problem of poor handlability.
In addition, if the film is cut as has been described above, it results in such a portion of the photosensitive film that can not be used for the image preparation which wastefully consumes the expensive photosensitive film and increases the operating cost. Further, in a case where the length of the photosensitive film is previously increased for transportation, as has been described above and a marking for distinguishing is applied to the increased portion, the image preparing area and the marking position may sometimes overlap with each other, by which an image is absent in the marking position after the image formation, by which complete transfer image can not be obtained.